Rechargeable NiMH batteries have become the batteries of choice for many applications ranging from consumer applications such as laptop computers and cell telephones to large scale applications such as electric vehicle (EV) propulsion and hybrid electric vehicle (HEV) propulsion systems.
For example, Ni--MH batteries, such as those described in copending U.S. patent application Ser. No. 07/934,976 now U.S. Pat. No. 5,277,299 to Ovshinsky and Fetcenko, the disclosure of which is incorporated herein by reference, have high energy and power densities, contain no toxic materials, can be rapidly recharged and have become the batteries of choice for both EV and HEV applications as well as consumer product applications. The fundamental principles of the technology incorporated in such batteries is disclosed in U.S. Pat. No. 4,623,597--Ovshinsky et al.
Some highly efficient electrochemical hydrogen storage materials have been formulated based on the principles set forth in the aforementioned U.S. Pat. No. 4,523,597. The present invention is based on fundamentally new discoveries relating to the compositions, structures, electron concentrations and local order and environment of such hydride materials having particular application as materials for the negative electrodes of NiMH batteries. The new hydride materials of the present invention provide an even higher density of accessible, reversible hydrogen storage sites in a preferred spectrum with superior kinetics and other properties and exhibit substantially improved and superior performance characteristics in NiMH batteries.